1. Field of the Invention
This invention relates generally to terminal clips or edge clips for attachment to a contact pad on a circuit-bearing chip or board. The clip is preferably of the type wherein solder is mechanically connected with the clip in a position to be melted for bonding the clip to the contact pad. More particularly, the invention relates to a strip of such terminal clips carried at one of their ends by a carrier strip, and wherein the free ends of the clips are supported by an auxiliary support, whereby a strip of such clips is securely supported in position while being attached to a circuit-bearing chip.
2. Prior Art
Various clips are known in the art wherein a quantity of solder is associated with the clip so that when the clip has been positioned on a contact pad of a circuit-bearing chip and the assembly heated, the molten solder covers the adjacent surfaces of the clip and pad to form, when cool, a metallurgical joint between the clip and pad. For instance, terminals of this type with various arrangements of solder-holding and/or pad-contacting fingers are disclosed in Seidler U.S. Pat. No. 4,120,558 and U.S. Pat. No. 4,203,648, in each of which the body portion from which the fingers are formed is flat and wide enough so that each of the fingers will have adequate strength for its intended purpose.
Increasing commercial pressure for miniaturization of the circuit bearing chips and the clips or terminals associated therewith requires reduction of the size and spacing (pitch) of the contact pads and the clips. Since the pads are fully supported by the material of the chip, no difficulty is encountered with the reduced spacing of the pads. However, the terminals or clips which are attached to the pads must have at least enough inherent strength to be self-supporting as they are applied, and to maintain good electrical contact with their respective pads while being soldered. Reduction in the size of the clips in order to accommodate the reduced spacing of the contact pads makes the clips relatively flimsy. It is not economical to increase the gauge of the strip from which the terminals or clips are stamped, since a very thin strip is electrically satisfactory. As the clips become smaller and more fragile, there is an advantage to having them carried at both ends during the manufacturing process. However, this is not always possible when the clips are severely formed.
In order to overcome these problems, some manufacturers make the clips in discrete, short lengths and then form them. This procedure obviously increases the handling problems substantially, and makes such a process economically impractical.
Further, in some applications, the clips have stem ends which are adapted to extend through holes in circuit boards. Miniaturization of the circuits results in the holes being spaced very closely together, with resulant thin walls and weakness between adjacent holes.